Adaptive control on flexural waves by a piezoelectric-based elastic metasurface with hybrid shunting circuits

Abstract

In aspects of its simple configuration and tunability, piezoelectric-based metasurface has benefited over its mechanical counterpart in adaptive wavefront manipulation. By tuning the circuitry elements in the shunting circuits properly, the equivalent material properties of the metasurface can be modified to attain a complete $2\pi$ phase shift and to maintain high transmission at desired working frequencies. In this paper, a piezoelectric-based elastic metasurface with hybrid shunting circuits ($\mathit{\text{NC}}$–$\mathit{\text{LC}}$–$\mathit{\text{NC}}$ shunts) are proposed to adaptively control the propagation of flexural waves. Through tuning of negative capacitance and inductance simultaneously, the proposed elastic metasurface can cover a phase shift ranging from $0-2\pi$ while having a high transmission ($\ge$0.7). It is discovered that any similar metasurface structural design with solely single shunting circuit presently available could not achieve the same results as the proposed elastic metasurface. In addition, analytical modeling based on equivalent Young’s modulus is developed and a finite element model is built to study the transmission and phase shift of the proposed metasurface. It is demonstrated numerically that the proposed piezoelectric-based elastic metasurface is capable of performing switchable functionalities, such as wave refraction and focusing, at different working frequencies (3500 Hz, 5000 Hz, etc.).

Graphical Abstract

HIGHLIGHTS

• Utilization of hybrid shunting circuits in designing a more compact metasurface design.

• Establish an analytical model based on equivalent Young’s modulus to predict effective range of circuitry elements.

• Build a finite element model to study the transmission and phase shift of the piezoelectric-based metasurface.

• Cover a full $2\pi$ phase shift and maintain high transmission through tuning negative capacitance and inductance simultaneously.

• Perform switchable functionalities at different working frequencies.

Keywords:

• Adaptive control
• hybrid shunting
• inductance
• metasurface
• negative capacitance
• piezoelectric

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Additional information

Funding

The work described in this paper was supported by City University of Hong Kong under Project No. ARG 9667238.